The Brazilian state of Roraima, in the country's northern region, is facing the worst flood since 1976, local authorities said on Monday.

The level of the Branco River rose 10.02 meters, surpassing the 9.8-meter level in 1976, isolated several areas and flooded 80 percent of the neighborhoods in Roraima's capital city Boa Vista. It also blocked main federal highways in the state.

Authorities declared state of emergency in almost all municipalities of Roraima. Governor Jose de Anchieta declared public calamity in the state on Sunday.

The governor requested help from the armed forces and traveled to Brazilian capital Brasilia for federal help. He will meet with National Integration Minister Fernando Bezerra de Souza.

Over 400 people had to leave their homes and schools in the affected areas suspended activities, leaving 25,000 children without classes. According to Colonel Kleber Gomes from the local Civil Defense services, the isolated municipalities still have supplies for some weeks, but after that, they will need help.